Size Matters: What Air Conditioner Size Do I Need?

 In Residential Air Conditioner System, Tips

When it comes to your air conditioner, size really does matter. But in the same breath, bigger is not always better. In fact, it all depends on several things.

The first thing that probably comes to mind is the size of the room you are trying to cool down. However, there are many other factors that might slip your mind when you are about to hit ‘add to cart’.

Why is the air conditioner size important? Well, not only to get the perfectly cool room temperature but it can also help save you some money and cut down on your monthly energy use.

Never buy an air conditioner in haste, you should always ensure that you have done your research to determine whether you are buying the correct unit for your space.

How Do You Measure Air Conditioner Size?

In Australia, air conditioning power is calculated in British Thermal Units (BTUs). The output of your air conditioner is calculated in kilowatts (kW). Furthermore, how effective your air conditioner is will be indicated by a star system. In short, the more stars your air conditioner has – you guessed it – the more effective and powerful it is.

Most units will need to be a minimum of 80 watts per square metre of the room you are looking to cool.

Why Does Size Matter?

In short, whether your air conditioner is too big or too small, both will result in higher than normal energy usage and therefore electricity bills. We explain why below.

If Your Air Conditioner is Too Big

It all comes down to power and your air conditioner either working over- or under-time. If you choose an air conditioner size that is too large, it will result in it cooling your space too quickly, triggering it to switch off before it has even completed the entire cycle it should. Since it’s switched off, the room will slowly start to heat up again, finally triggering the air conditioner to switch back on again.

This on-and-off-again action will really use up a lot of energy and result in hefty bills at the end of the month. Over and above the running cost of the incorrect air conditioner size, the room can also either be too hot or too cold at all times – effectively rendering the air conditioner useless! At the same time, you might feel uncomfortable simply because the air humidity is just not right. In the long run, it can also cause damage to your air conditioner unit.

If Your Air Conditioner is Too Small

On the other hand, if your air conditioner is too small, it will have to work overtime in order to adequately cool down your indoor space and it won’t run efficiently the way it is supposed to. Because it will have to work overtime in order to cool down your space properly, it will also result in sky-high electricity bills.

Other than costing you money, it will also cause wear and tear to your air condition unit as well as make you feel uncomfortable due to the fact that the air would dry out too much.

When Push Comes to Shove

If you have to choose an air conditioner that is not 100% the right fit, rather opt for an air conditioner with a slightly bigger rather than smaller capacity.

Top Factors to Consider When Choosing an Air Conditioner Size

Sized Up: Room Size

The first one is an obvious one and you should always consider this first. You might think that it’s just about the square metres, but the volume is what really matters. For example, length, width as well as ceiling height. It goes without saying that, if your room has really high ceilings, it will need more energy to cool down the entire space.

Take a look at our table below to further guide you.

Size Matters: What Air Conditioner Size Do I Need? 1
source: CHOICE

Location, Location, Location 

Not all climates are created equal and should be taken into consideration when purchasing your air conditioner. In the warm Perth summers, you should opt for something with enough power to cool not only the size of your room, but that is also strong enough to cool down the climate you find yourself in.

In the general Western Australia region, you will most probably need an air conditioner unit of about 2.8kW.

All About That Insulation

Consider whether any part of the room is insulated. What is underneath the flooring and above the ceiling? Insulation has a very big effect on the temperature control of your room.

Don’t have any ceiling insulation? You might want to consider installing this before getting your air conditioner as it will save you a lot of money in the long run. It will keep in the cool air and you will likely be able to go for a smaller air conditioner.

Orientation of Air Conditioner 

Which way is the room you are trying to cool facing? If it is facing in the northern or western direction, it can get quite hot in the warmer months so you will need to take that into consideration as the air conditioner will need enough power to work properly. If the room is facing south, it tends to be cooler.

How Do I Calculate the Size of the AC I’ll Need?

There are two options for calculating the size of the air conditioner you will need. The first option is a little bit more accurate, although the second one will still work well enough if accuracy is not that important to you.

Option 1 – Go Pro: Consult a Professional to Determine Air Conditioner Size

First things first, the best solution to determine the ideal air conditioner size for your space is to contact a professional when you’re ready to install a new unit. They do this daily and will be able to save you time (and potentially money if you end up making the wrong choice!).

Option 2- Do Some Maths: A Formula to Determine Air Conditioner Size

Grab your measuring tape and let’s get calculating! This formula won’t take long and is fairly easy. Although this is also an effective method, it is not the most accurate method. So, if you need something more exact, you should rather opt for the first option mentioned above.

Steps of the Formula:

1)  First find out the estimated amount of air conditioning you will need for your space. In order to determine this, you will need to find out the area of the room.

2)  Do this by establishing the length and well as the width of every room and then multiply them. (Length of room X width of room)

3)  Find the total sum of all of the room areas in square metres.

4)  This is the stage where your ceiling height comes into play:

–       If this height is 2,4m high, the area in square metres would have to be multiplied by 150 watts.

–       If it’s 2,7m high, multiply your living area by 160 watts.

–       In the case that it’s 3m high, multiply the area with 175 watts.

5)  By using the above calculation, you will be able to determine the number of watts you need.

6)  Just move the decimal three points to the left to convert it into the kilowatts number you are looking for.

Example: area = 100 square metres X 150 watts (based on height of 2,4m ceiling height) = 15,000 watts. Then you move the decimal to give you a total of 15 kilowatts. Therefore, the air conditioner size that will most likely work for this space should be an air conditioner of 15kW.

Option 3 – Use an Online Calculator

Yes, there are many online calculators out there. However, do not consider them to be the law as they can sometimes be inaccurate. However, if you are just looking for a starting point or benchmark, it’s a good place to start in order to give you a general indication of the air conditioner size you need.

Still Unsure What Air Conditioner Size You Should Go For?

If you’re still not convinced which air conditioner size you will need to cool your Perth home, office of business, don’t panic.

We understand that there are so many different options out there that it can be near impossible to decide on one. At All Air Services we ensure that we get you the very best air conditioner size and model to meet all of your daily requirements. Getting the right air conditioning unit really brings comfort into your everyday lifestyle, all year round – especially in the height of summer in Perth.

Don’t delay, contact us today so that we can break things down so that you can cool things down in your building.

Recent Posts

Start typing and press Enter to search

0
Air purifier - what does it do?Where Should I Install My Air Conditioner